Pipe bending apparatus



y 3 W33 R. H. HENDERSON PIPE BENDING APPARATUS 2 Shets-Sheet 1 Filed Jan. 8, 1930 IN VEN TOR,

II I Lldllllllilllllil y 23, 1933- R. H. HENDERSON PIPE BENDING APPARATUS Filed Jan. 8. 1930 2 Sheets-Sheet 2 INVENTOR.

BY .2 g 7 ATTORNEY.

Patented May 23, 1933 UNITED STATES PATENT OFFICE -BOBE3'I' nmm', HENDERSON, OF EAST ORANGE, NEW JERSEY PIPE SENDING APPARATUS Application fled January 8, 1980. Serial No. 419,230.,

This inventionrelates, enerally, to improvements in apparatus or bendlng pipe, metallic electric conduit, and other rigid metallic tubular forms.

This invention has for its princ pal object to provide a simple and eflicient apparatus for producing desired bends in metallic pi e or conduit without any a preciable distortion, such as flattenin t e same in cross-section, kinkln or wrink mg; while at the same time rovi ing a powerful means, easily actuated y hand, for making such bends rapidly, and without the necessity for the exercise of any espec al skill by the operator. With this end 1n View, the present invention provides a pipe bending apparatus whichmay be designated a bench bender to distinguish the same from hand benders known to the art as hickeys.

This invention has for a further object to provide a novel construction of pipe bending apparatus comprising essential y a fixed base sector and a movable knead ng or molding bar or rack; these parts hav ng opposed pipe embracing grooves, and being inte'rmeshed at both sides of the latter by cooperating gear teeth with which the arts are each provided, thus progressively a rding complete embracing support to the plpe or conduit at the points where bending pressure is applied, step .by step, until bends of a desired degree are completed; means being further rovided for progressively rockm or movin the kneading or moldin bar re ative to t e fixed base sector, wit powerful applied pressure, whereby the desired curvature is produced in the pipe or conduit.

This invention has for a further object to provide novel cross-sectional conformation of both the base sector and bar or rack pipe embracing grooves, whereby compensating spaces are furnished to allow for molecular adjustment of the pipe or conduit body during bending operations, without subjecting said pipe or conduit to undue or distorting stresses or strains during the bending operations.

Other objects of this invention, not at this time more particularly enumerated, will be understood from the following detailed description of the same,

Illustrative embodiments of this invention are shown in the accompanying drawings, in which Fig. 1 is a top plan view of a pipe bending apparatus made according to this invention; Fi 2 is a side elevation of the same, viewe in the direction of the arrow 2 in Fig. 1; Fig. 3 is a vertical section on an enlarged scale, taken on line 33 in Fig. 1; and Fig. 4 is a fragmentary further enlarged section across the cooperating base sector and kneading or molding bar or rack, said view showing in greater detail the compensating spaces in the contours of the pipe embracing grooves of these parts.

Fig. 5 IS a top plan view of a somewhat modified form of the pi e bending apparatus made according to t is invention.

Similar characters of reference are employed in the above described views, to indicate corresponding parts.

, Referring to said drawings, the reference character 6 indicates any suitable form of base frame or bed plate upon which the novel bending devices are mounted. Fixed to and upstanding from the upper surface of said base frame 6 is a post 7. Fixedly secured to said post 7, so as to be non-rotat- 8o able, .is a base sector 8, the circumference of which preferably exceeds one-hundred and eighty degrees. Said base sector 8 is provided in its periphery with a pipe emracing groove 9, in both marginal sides of which are cut gear teeth 10. The radius of said base sector 8, from its center to the bot tom of the pipe embracing groove 9 thereof, is such as to correspond to the radius of a bend desired to be formed in pipe or conduit-submitted to the o eration of the apparatus. The depth 0 the groove 9, inwardly from the pitch diameter of the gear teeth 10, is approximately equal to the radius or one-half the outside diameter of the pipe or conduit to be bent, while the width of the groove 9, in the plane of the pitch diameter of the gear teeth 10, is slightly in excess of the outside diameter of the pipe or conduit to be bent. The inner I00 sides of the groove 9 are parallel in their outward extension from the pitch diameter of the gear teeth 10 to the exterior ends of the latter. I

The reference character 11 indicates a movable rectilinear kneading or molding bar or rack of a length approximately the circumferential extent of said base sector 8. Said kneading or molding bar or rack is provided, in an edge face thereof, with a pipe embracing groove 12, in both marginal sides of which are cut gear teeth 13 adapted to cooperatively intermesh with the gear teeth 10 of said'base sector 8. The depthv and width of said bar or rack groove 12 corresponds to that of the groove 9 of said base sector 8,to which the same is opposed when the bar or rack is operatively related to said base sector, whereby a pipe or conduit 14 engaged between said operatively assembled base sector and bar or rack is entirely surrounded and embraced at the point of impingement on said base sector by the combined wall surfaces of the cooperating and opposed grooves 9 and 12.

Fixed on said base frame 6, adjacent to one end portion of the base sector 8, is a holder post 15 having, in the side thereof .toward the base sector 8, a pipe receiving seat 16. Threaded into the upper end of said holder post 15 is a manipulatable screw 15' adapted to engage a pipe entered in said seat 16 so as to anchor the same securely against longitudinal movement.

Means for applying aperative power to the movable kneading or molding bar or rack 11 is provided. In one form of my novel pipe bending apparatus, as illustrated in Figs. 1 to 3 of the drawings, said power applying means comprises a pair of radial links 17 and 18. Said link 17 being pivotally related to the post 7 so as to extend outwardly therefrom along the under side of said base sector 8, and said link 18 being likewise pivotally related to the post 7 so as to extend outwardly therefrom along the upper side of said base sector 8. The outer free ends of said links extend over and beyond the bar or rack 11, when the latter is operatively assembled with said base sector 8. Pivotally mounted between the ends of said links 17 and 18, outwardly of the bar or rack 11, is an eccentric cam 19, the same being mounted on a fulcrum pin 20 which is arranged to extend through openings 21 pro-' vided in the links 17 and 18. Connected to extend from the cam 19 is a handle lever 22. Said cam 19 is preferably provided with a fiat face 23, which, when brought parallel to the back or outer face of the bar or rack 11 provides a space suflicient to permit disengagement of the bar or rack teeth from the teeth of the base sector, so that the bar or rack may be withdrawn endwise from its operative assembled relation, when entering or removing pipe or conduit from thn appaform comprises a lever-'24 pivoted on the post 7 to extend outwardly therefrom beneath the base sector 8 and bar or rack 11. Fixed on a stud 25 carried by said lever 2 L is a roller 26 to engage the outer face or back of the bar or rack 11; the lever 24 terminates at its free end in a handle member 27. This form of power applying means is well adapted to actuate the bar or rack -11 in the bending of comparatively soft or ductile metallic tubes, pipe or conduit, such e. g. as copper tubing, and also for bending pipe and conduit of small diameters.

The cross-sectional shapes of the respective grooves 9 and 12 of the base sector 8 and bar or rack 11, is of a conformation adapted to provide compensation expansion spaces. In the base sector groove 9, these compensation expansion spaces lie about forty-five degrees from and on each side of the longitudinal center of the bottom of the groove 9, and are indicated by the reference character 28 in Fig. 4; and, in like manner, in the bar or rack groove 12, these compensation expansion spaces lie about forty-five degrees from and on each side of the longitudinal center of the bottom of the groove 12, and are indicated by the reference character 29 in Fig. 4. The functions of these compensation expansion spaces is similar to like spaces provided in the bending groove disclosed in my prior United States Letters Patent for Hickey No. 1,627,- 034, dated May 3, 1927, in which patent said functions have been described in great detail. If the wall of the pipe to be bent is relatively thick in proportion to its diameter, these compensating expansion spaces do not need to be as deep as they do if thin Wall tubing is to be bent, especially if such tubing is made of steel. Thin wall copper and brass tubing, on the other hand, because more ductile, does not require deep compensating expansion spaces in the grooves 9 and 12 becausethey more readily conform to the groove contours under the operation or pressure of the bar or rack.

In operation of the bending apparatus, the pipe or tube desired to be bent is placed in the groove 9 of the base sector 8, adjacent to one end of the latter and so as to lie tangent to the bottom of the groove; the

. same, the kneading pipe or tube being also engaged in the seat 16 of the holder post 15. The pipe or tube is longitudinally adjusted to relate the same to the base sector so as to assure the production of the bend at the desired point, whereupon the clamp screw 15' is tightened to grip and anchor the pipe or tube against displacement during the bending operations. The pipe or tube being thus related to the base sector 8, preparatory to bending the or molding bar or rack 11 is engaged agalnst the outer side of the pipe or tube so that the latter is embraced by the groove 12 thereof, while the teeth 13 of bar or rack are at the' same time brought into mesh with the teeth 10 of said base sector 8.

When using the form of power applying means shown in Fig. 5 and above described, the pipe or tube is bent'by the operator to any required angle by advancing the roller 26 alon the bar or rack 11 b swin in for-.

ward the handle member 27, thus rocking the bar or rack toward the base sector which progressively meshes the teeth of the former with the teeth of the latter. The progressive movement of the bar or rack 11 toward the base sector 8 bends the pipe or tube about the circumference of the latter while embraced by the groove 9 thereof; the groove 12 of the bar or rack functioning to knead and mold the pipe or tube into conformity to the longitudinal curvature of the base sector groove 9 without subjecting the pipe or tube to abnormal or undesired distortion.

When using theform of power applying means shown in Figs. 1 to 3 inclusive, the

pipe or tube is assembled relative to the base sector 8, bar or rack 11 and holding post 15 in the same manner as already above described. In bending the pipe or tube, the operator swings back the handle lever 22 to dispose the short radius of the cam 19 in opposition to the back of the bar or rack 11, at the same time sliding the cam forward with the swing of the links 17 and 18 as far as the short radius of said cam will permit,

whereupon the operator swings the handle lever 22 forward to turn the cam as far as it will go, thus rocking the bar or rack on the sector and thereby producing a definite bend in a portion of the pipe which is embraced between the base sector and bar or rack. After such operation, the rotation of the cam is reversed, and the operation is progressively repeated until the desired extent of bend is produced. It will thus be seen that between each bending step there is an interval of rest or relaxation of applied bending pressures on the pipe or tube while the cam is being re-disposed. These intervals of rest are of advantage to the bending process, since they allow the pipe or tube time for readjustment of its molecular structure, that is to breathe, so to speak, under the kneading or molding operations taking place in the combined embrace of the cooperating grooves of the base sector and bar or rack. In other words the well known and effective step by step action common to manipulation of the hand hickey is simulated in my novel bench bender.

The efiicient kneading and molding action exerted by the opposed grooves 9 and 12 of the base sector 8 and bar or rack 11, especially when bending pipe or conduit consisting in thin wall steel tubing, is materially advanced by the contour forms of the said grooves. This will be better understood from the following description read in connection with Fig. 4 of the drawings.

When pressure is applied to the bar or rack 11 during a bending step, the bending force acts primarily on the axis A-A'. The pressure thus exerted causes a temporary shortening of the cross-sectional radii O1 and 0-2 of the pipe or conduit, and a consequent tendency to lengthening of the radii 0-3 and O4, until the sides of the pipe or conduit impinge upon the sides of the combined grooves 9 and 12 formed by the intermeshing gear teeth 10 and 13, and on a line intersecting the pitch diameter of the gear teeth 10 of the base sector 8. The continued application of bending pressure, with its consequent strain upon the pipe or conduit walls, causes the latter to temporarily expand into the con'ipensating expansion spaces 2829, with resultant lengthening of radii ()M, ()--L, OP and OR. These compensating expansion spaces 28-29 are preferably designed with regard to the particular pipe or tubing to be bent with the purpose of limiting the expansion permitted along the lines of the radii O-M, O-L, ()P and OR, to a fairly close approximation of the elastic limit of the material from which the pipe or conduit is made, some variation in this respect existing as to materials such as steel, copper, brass, etc. Thin wall steel pipe (for example, requires deeper compensating expansion spaces than does pipe made of copper, brass or other more ductile metals.

After completion of a bending step, and relaxation of the pressure of the cam 19, if the pipe were removed from the apparatus and the bend examined, it would be found that the radii O-1 and O2, on relaxation of bending pressure, had lengthened and radii O-3 and 0-4 had shortened, and that the pipe Walls temporal-i1 expanded on radii ()-M, ()L, OP am ()--R had contracted again to normal; in other words, the various radii would be all substantially of same length, and the pipe at point of bend would be free of any distortion, such, e.g. as flattening, kinking or wrinkling. The smooth even bending of the pipe or conduit is primarily due to the factors inherent in the novel construction and desi n of my bending apparatus, viz., first, t e meshed condition of the base-sector and bar or rack at both sides of the pipe or conduit, whereby the sides of the bending grooves 9-12 provide adequate and complete support for both sides of the pipe or conduit to an extent approximating about one and onehalf the diameter of the pipe or conduit each way from the oint at which the bending force is chie y exerted, and, second, the provision of the compensating ex-' pansion spaces 2829 in the respective rooves 9 and 12, which furnish what may be termed breathing spaces, for the stressed metal, and whlch permit of manipulation, movement and rearrangement of the molecular structure of the pipe or conduit walls during and between each step by step movement of the bending operations.

I am aware that various changes could be made in the above described construction of pipe bending apparatus as well as in the details of the structure thereof, without departing from the scope of this invention, and therefore it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim a 1. A pipe bending apparatus, comprising a fixed base sector having a peripheral pipe receiving groove bounded on each side by gear teeth, a movable rectilinear molding bar also having a pipe embracing roove bounded on each side by gear teeth a apted to mesh with the gear teeth of said base sector, the pipe to be'bent being receivable between said base sector and molding bar vso as to be embraced by the grooves thereof,

means to anchor the pipe against displacement'during the bending operation, power -applying means to rock said bar on said base sector and in bending relation to the pipe, the depth of said base sector and molding bar grooves measured from the pitch lines of their gear teeth substantially conforming to the radius of the pipe to be bent, the width of said grooves substantially conforming to the diameter of the pipe to be bent, and said groovesbeing of increased radial depth at points intermediate their bottom and sides to provide clearance spaces at such points between their walls and a pipe entered therein.

2. A pipe bending apparatus, comprising between said base sector and molding bar so as to be embraced by the grooves thereof, means to anchor the ipe against displacement during the bending operation, power applying means to rock said bar on said base sector and in bending relation to the pipe, said means comprising a pivoted support radial to said base sector, a rotatable bar-actuating cam carried by said support, and a handle member for rotating said cam.

3. A pipe bending apparatus, comprising a bed-plate, a main post up-standing from said bed-plate, a base sector fixed on said post, said base sector having a peripheral pipe receiving groove bounded on each side by gear teeth, a movable rectilinear molding bar also having a pipe embracing ove bounded on each side by gear teeth a apted to mesh with the gear teeth of said base sector, the pipe to be bent being receivable between said base sector and molding bar so as to be embraced by the grooves thereof, a holding post fixed on said bed-plate adjacent to one end of said groove of said base sector, said holding post having a seat to receive a pipe, means to clamp the pipe in said post seat to hold the same against displacement durin the bending operations, and power applying means to rock said bar on said base sector and in bending relation to the pipe, said latter means comprising a support pivoted to said main post radial to said base sector, a rotatable bar-actuating cam carried by said support, and a handle member for rotating said cam.

4. A pipe bending apparatus, comprising a bed-plate, a main post up-standing from said bed-plate, a base sector fixed on said post, said base sector having a peripherial pipe receiving groove bounded on each side by gear teeth, a movable rectilinear molding bar also having a pipe embracing groove bounded on each side by gear teeth adapted to mesh with the gear teeth of said base sector, the pipe to be bent being receivable between sa1d base sector and molding bar so as to be embraced by the grooves thereof, the depth of said base sector and molding-bar grooves measured from the pitch lines of their gear teeth substantially conforming to the radius of the pipe to be bent, the width of said grooves substantially conforming to the diameter of the pipe to be bent,

said grooves being of increased radial depth at points intermediate their bottoms and sides to provide compensating expansion spaces at such points, a holding post fixed on said bed-plate adjacent to one of said grooves of said base sector, said holding post having a seat to receive a pipe, means to clamp the pipe in said post seat to hold the same against displacement during bending operations, and power applying means to rock said bar on said base sector and in bending relation to the pipe,

5. A ipe bending apparatus, comprising a bed-p ate, a main post up-standing from said bedlate, a base sector fixed on said post, sai base sector having a peri heral ipe receiving groove bounded on eac side y ar teeth, a movable rectilinear molding at also havin a ipe embracing oove bounded on each side y r teeth a apted to mesh with the gear tee of said base sec- 10 tor, the pipe to be bent being receivable between said base sector and molding bar so as to be embraced by the grooves thereof, the depth of said base sector and molding bar grooves measured from pitch lines of their 7 35 gear teeth substantially conforming to the radius of the pipe to be bent, the width of said grooves substantially conforming to the diameter of the pipe to be bent, said grooves being of increased radial depth at points in- 20 termediate their bottom and sides to provide compensating expansion aces at such points, a holding post fixe ,on said bedglate adjacent to one of said grooves of said ase sector, said holding post havingl a seat 25 to receive a pipe, means to clamp t e pipe in said post seat to hold the same against displacement during bending operations, an power applying means to rock said bar on said base sector and in bending relation 30 to the pipe, said latter means comprising a support pivoted to said main ost radial to said basesector, a rotatable ar-actuating cam carried by said support, and a handle member for rotating said cam.

36 In testimony, that I claim the invention set forth above I have hereunto set my hand this 6th da of January, 1930.

' ROBE T HALSEY HENDERSON. 

